Hey Drakesbane,
You probably aren't do anything wrong whatsoever. The fact is Cleric/Templar adepts are extremely rare, because if they do drop, they're usually nbg'd, or if not, sold to the merchant. The few that do make it to the broker/blackmarket are immediately snatched up. To make broker searches more effective, try setting the parameters to spell scrolls, with the minimum con grey, and max. con orange.
Realistically, you're going to have to settle on app3s for the most part, and with higher level spells, depending on your server, app2s. The only thing we Templars can do is check the brokers everyday, and pray for some luck with drops.